This proposal is a request for continued partial funding of the Flow Cytometry Core Facility (FACS Core) within the UAB CFAR. The Primary purpose of the FACS Core are to make available to CFAR investigators access to the equipment, trained personnel, and expertise to perform cell analysis and purification with state-of-the-art equipment and techniques on a reasonable cost for services basis and to offer these services in a facility capable of handling potentially infectious material. The FACS Core employs a dedicated full-time experienced cytometer operator who has served about 60 users in 29 laboratories over the past year. The facility is equipped with a FACStar four parameter single laser cytometer/sorter; data handling is performed by a CONSORT 30 extended analysis computer system which incorporates two integrated Hewlett Packard HP 300 microcomputers. At present, the appropriate software to perform certain CONSORT 30-capable functions (univariate through tetravariate analysis via single or multiple histograms, contour graphs with appropriate statistics, DNA curve fitting, immune monitoring, reticulocyte/platelet analysis, and histogram overlapping with statistics software) is not available to the FACS Core. Accordingly, funding to purchase these applications is requested in this proposal. Sufficient funds are requested to insure stable salary support and continuing education for the operator and to cover the field service contract for the cytometer. The requested level of support will be sufficient to cover a significant proportion of the actual cost of operating the core and it is estimated that this will allow the present rate of $50/hour charged to Center investigators for use of the FACS Core to be sustained into the foreseeable future.